While mating behaviour in onychophorans has been documented in only a few species, it would appear that male reproductive strategies include both dermal and vaginal insemination. To add to this diversity, the males of many newly described species of Australian onychophorans display elaborate head structures. In some species, these head structures have been shown to carry spermatophores. Here we describe Florelliceps stutchburyae gen. nov., sp. nov., a species possessing a unique head structure. An account of its unusual mating behaviour is provided in which the male's everted head structure was placed against the female's gonopore and held there by the claws of the female's reduced last pair of oncopods. After the individuals separated, the female's genital opening was covered by a spermatophore and histological sections showed that sperm had been released into her reproductive tract. A review of mating behaviour in onychophorans is also included with a discussion of sperm acquisition by the female and its correlation with her reproductive cycle.
